Yep, it's the back and forth from London to Cardiff that's the killer for that. Trying to do it by public transport would be very inconvenient and I tend to travel with many bags and boxes. I'm trying to only come back once every two weeks, rather than every weekend. I'd love a car that uses renewable energy, I've even test driven a Toyota with battery / petrol engine but there was very little boot space ('cos of the batteries) and it didn't make much difference for motorway driving which is by far my longest type for driving.